Synthetic yarn filaments are traditionally produced by melt, wet or dry spinning techniques, each being very well known in the art. For the production of cellulose acetate filaments, the dry spinning technique has been utilized quite successfully in the past. That is, a solution (usually called a "dope") comprising cellulose acetate and a volatile solvent therefor (usually acetone) is typically extruded through spinnerettes into a gaseous medium which serves to volatilize and evaporate the solvent thereby forming filaments of cellulose acetate. Usually multiple filaments are extruded, gathered into a tow and made into a filter rod, which is subsequently used for cigarette filters in a manner well known in the art. Spinning, volatilization and evaporation normally occur in a vertical chamber commonly referred to as a cabinet.
At present, the gaseous medium is introduced into the spinning cabinets in such a way as to produce much turbulence and disturbance of the filament bundle which results in undesirable defects in the to band. This invention discloses an apparatus and method to introduce and retrieve this warm process gas so as to minimize these defects and maximize the heat and mass transfer between the tow and process gas.